1. Field of the Invention
The present invention relates to a working machine such as a hydraulic excavator including a guard cover, which covers pieces of apparatus.
2. Description of the Related Art
In an upper rotating body of a hydraulic excavator are disposed pieces of apparatus such as a working oil tank, a radiator, a main control valve, a multi control valve and a selector valve and the like. These are covered with a guard cover, and the maintenance of the apparatus or the like in the cover is performed by opening the cover.
In this case, the guard cover is large and heavy, its opening and closing are troublesome and further a space required for opening and closing the cover is large. Thus, a technology that an openable small window is provided in the cover and the apparatus or the like, which require daily maintenance, are provided in the guard cover so as to face this small window, has been known (see Japanese Patent Laid-Open Publication No. Hei. 10-219741).
Since the hydraulic excavator can be often left at the site after the completion of working, an openable locking mechanism by a key is provided in the cover so that the apparatus or the like are not operated freely by unauthorized persons. Further, in the case of providing the small window, a cover for opening and closing this small window is needed and use of the same locking mechanism in this small cover is also needed.
Namely, two sorts of locking mechanisms for the guard cover and the small window cover are required.
Here, if a key for both locking mechanisms is used in common, only one key is all that is required. However, the both locking mechanisms each require a key cylinder and a locking mechanism enough to satisfy at least safety standards.
Further, to attach a key cylinder a key-operating portion for the cylinder must be fixed to the guard cover. Thus, working for the cover is needed. The working machine of the related art has been disadvantageous in the points of the production steps, cost and appearance of the machine.
It is noted that even if another locking mechanism such as a card open-close type, a dial key or the like is used, it is not changed that two sorts of independent locking mechanisms are required.
Further, since the position of a locking mechanism of the guard cover and its open-close method can be seen from the outside easily by a key hole or the like, there was a problem that the possibility of breaking the locking by unauthorized persons is high.